The goal of this phase II/III prospective, multicenter, randomized, controlled trial is to compare the efficacy and safety of clarithromycin combined with either rifabutin, ethambutol or the combination of rifabutin and ethambutol for the treatment of disseminated Mycobacterium avium complex (MAC) disease in persons with AIDS, including individuals with or without prior MAC prophylaxis.(ACTG 223)